Apparatus for drawing liquids into, and expelling liquids from, a pipette or the like

ABSTRACT

Apparatus for drawing liquids into, and expelling liquids from, a pipette, including a body member comprising a hand grip portion and a pipette supporting portion. Duct means are provided in the body member in communication with one end of the pipette held by the pipette supporting portion. Valve means are mounted on the hand grip portion beneath the fingers of the user for selectively connecting the duct means to a vacuum source or an air pressure source.

United States Patent [191 Kenney [451 Sept. 10,1974

[ APPARATUS FOR DRAWING LIQUIDS INTO, AND EXPELLING LIQUIDS FROM, A PIPETTE OR THE LIKE [75] Inventor: James W. Kenney, Philadelphia, Pa.

[73] Assignee: Drummond Scientific Company, Broomall, Pa.

22 Filed: Feb.23, 1973 21 Appl. No: 335,367

[52] US. Cl. 73/425.6 [51] Int. Cl B0lb 3/02 [58] Field of Search 73/425.6, 425.4 P

[56] References Cited UNITED STATES PATENTS 3,719,087 3/1973 Thiers 73/425.6

Primary Examiner-S. Clement Swisher Attorney, Agent, or FirmShlesinger, Arkwright, Garvey & Dinsmore [57] ABSTRACT Apparatus for drawing liquids into, and expelling liquids from, a pipette, including a body member comprising a hand grip portion and a pipette supporting portion. Duct means are provided in the body member in communication with one end of the pipette held by the pipette supporting portion. Valve means are mounted on the hand grip portion beneath the fingers of the user for selectively connecting the duct means to a vacuum source or an air pressure source.

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APPARATUS FOR DRAWING LIQUIDS INTO, AND EXPELLING LIQUIDS FROM, A PIPE'ITE OR THE LIKE BACKGROUND AND OBJECT OF THE INVENTION Various methods and devices have been employed in the past for drawing liquid samples into pipettes including mouth pipetting, the use of rubber sucker tubes, and a variety of hand-operated syringe-type devices. All of these methods have been found to have disadvantages in actual use. The problem with mouth pipetting and the use of rubber sucker tubes is that, on occasions, when it is desired to pipette dangerous or noixious materials, the fumes are inhaled, with resultant harmful effects. The hand operated syringes although avoiding the disadvantages of mouth pipetting, are tiresome to operate when pipetting repetitive liquid samples.

More recently, mechanical devices have been developed for drawing liquid samples into pipettes as illustrated by US. Pat. No. 3,310,002 granted Mar. 21, 1967, and US. Pat. No. 3,463,013 granted on Aug. 26, 1969. While these mechanical devices overcome the objections of the above methods and devices for pipetting fluids, the structure thereof is cumbersome to operate, thereby reducing the facility with which liquid samples may be drawn into and expelled from, the pipette and also causing fatigue after repeated use.

It is therefore an object of this invention to provide apparatus for drawing liquids into, and expelling liquids from, a pipette, which includes a hand-held body member to which a pipette is attached, the body member being provided with valves underlying the fingers when in the position of use and selectively operable to apply either a vacuum or an air pressure to one end of the pipette for drawing the liquid into, and expelling the liquids from, the apparatus.

Another object is to provide apparatus of the character described which is adapted to be readily held in the palm of one hand with the fingers easily and naturally movable to actuate valves strategically positioned on the hand grip portion thereof.

A further object is to provide apparatus of the char acter described which is of simple construction, and in which a pipette may be quickly attached thereto for expeditiously filling and emptying pipetes without fatigue.

A still further object is to provide a valve operated apparatus of the character described wherein said valves are constructed to allow varying degrees of communication between the pipette and the vacuum or air pressure source, to permit filling and emptying of the pipette at the desired rate.

Other objects will be manifest from the following description of the preferred form of this invention, taken in connection with the appended drawings.

DESCRIPTION OF FIGURES OF THE DRAWINGS FIG. I is a side elevational view of the apparatus of the present invention, illustrating its use;

FIG. 2 is an enlarged sectional view taken along the line 2-2 of FIG. 1, looking in the direction of the arrows;

FIG. 3 is a sectional view taken along the line 33 of FIG. 1, looking in the direction of the arrows;

FIG. 4 is a sectional view taken along the line 44 of FIG. I, looking in the direction of the arrows;

FIG. 5 is a sectional view taken along the line 5--5 of FIG. I, looking in the direction of the arrows;

FIG. 6 is an enlarged sectional view of the valve members forming a part of the present invention, showing one valve in inoperative position, and the other valve in operative position, and

FIG. 7 is a view similar to FIG. 6, but showing the valve members in reverse operational position.

DESCRIPTION OF THE INVENTION The apparatus of the present invention generally includes a body member 16 for holding a standard pipette 18 which body member is connected by a pressure line 20 to a source of air pressure 22 and by a vacuum line 24 to a vacuum source 26. As indicated in FIG. 1, these lines may be coaxially positioned with respect to each other.

Body member 16 is preferably of U-shape configuration, the central portion of which provides a hand grip 28 and the leg portions of each, designated 30 and 32, provide spaced means for supporting and holding pipette 18.

The outer terminal of leg portion 32 is provided with an arcuate recess forming a saddle 34 of generally semi-circular shape in cross-section for receiving an intermediate portion of pipette 18. A continuous spring member 36 extends through a transverse bore 38 in member 32, which spring extends across saddle 34 for holding the pipette in position during filling and emptying thereof.

When pipette 18 is in the position show in'FlG. I, the upper end thereof engages a grommet seal 42 secured to leg portion 30 in facing relation to saddle 34. Seal 42 has a central aperture 44 which communicates with a duct 46 in leg portion 30. Duct 46 communicates with a duct 48 extending longitudinally of leg portion 30, which duct in turn communicates with a duct 50 extending partially through, and longitudinally of, hand grip 28. Duct 50 communicates with the lower portion of a valve bore 52, which bore is in communication with a like spaced valve bore 52' by means of a connecting duct 51. Valve bores 52 and 52' house a pair of like valve assemblies designated 54 and 54' respectively.

As shown in FIGS. 1, 6 and 7, valve assemblies 54 and 54 are of like construction and include sliding valves 56, 56' which are in sliding engagement with the walls forming reduced sections of the upper portion of bores 52 and 52', which valves have actuating buttons 58, 58' secured to the upper terminals thereof. Beneath valves 56, 56' are convolute springs 60, 60' mounted in the valve bores, the upper ends of which springs engage the lower terminals of valves 56, 56', and the lower ends of which springs engage combination caps and spacers 62, 62', which are in threaded engagement with the lower end wall portions of the bores. Caps and spacers 62, 62' include integrally formed cylindrical portions 64, 64' in surrounding relationship with convolute springs 60, 60.

Under urging of springs 60, 60, valves 56, 56' are normally urged to the inoperative position shown in FIG. 1. Pairs of spaced O-ring seals including upper seals 66, 66' and lower seals 68, 68 are in peripheral engagement with the lower ends of valves 56, 56 and fixed to hand grip portion 28 on both sides of ducts 50 and 51, the seals lying proximate the lower ends of valves 56, 56' when the latter are in the inoperative position of FIG. 1. Valves 56, 56 are provided with longitudinally extending grooves 70, 70 located in the peripheral walls of the valves, which grooves lie above sealing rings 66, 66 out of communication with dust 50 when the valves are in the inoperative position. As also shown in FIGS. 6 and 7 when either valve is in the operative position, longitudinal grooves 70 or 70' are in communication with duct 50 or duct 51.

It is a salient feature of the present invention to form grooves 70, 70 t of non-uniform cross-sectional area throughout their length. This is effected by providing tapered inner groove walls 72, 72' so that the groove is progressively more shallow from the top to the bottom thereof. In this way, controlled communication with pipette 18 is effected, thereby regulating the rate of filling and/or emptying the pipette.

Hand grip 28 is further provided with a pair of air ducts 74 and 76 which extend through a fitting 78 threadedly engaged with body member 16. Ducts 74 and 76 pass through coaxial tubular extensions 80'and 82 carried by fitting 78, said tubular extensions being engaged with vacuum line 24 and air pressure line respectively. Duct 74 is in communication with valve assembly bore 52 and duct 76 is in communication with valve assembly bore 52.

Therefore, as shown in FIG. 6, when valve 56 is depressed by operation of button 58, the movement of groove 70 into communication with duct 50, also effectively establishes communication between vacuum source 26 and pipette 18 through duct 74, valve bore 52, groove 70, ducts 50, 48 and 46, and bore 44 of grommet seal 42. In like manner, when button 58' is depressed as shown in FIG. 7, communication is effected between air pressure source 22 and pipette 18 through duct 76, valve bore 52. groove 70', connecting duct 51, valve bore 54, ducts 50, 48 and 46, and bore 44 of grommet seal 42.

Valves 56, 56 are further provided with central longitudinal bores 84, 84 which, when the valves are in the inoperative position shown in FIG. I, extend from a point above hand grip portion 28 to a point in alignment with duct 72. Bores 84, 84 are provided with upper vents 86, 86 and lower vents 88, 88' and establish communication between duct 74 and 76 and the atmosphere, while the valves are in the inoperative position shown in FIGS. 1 and 6. When valves 56, 56' are depressed, vents 86, 86' are no longer open to the atmosphere and communication between the pressure or vacuum sources and the atmosphere is closed.

OPERATION In use of the apparatus of the present invention, pipette 18 into which a liquid sample is drawn is placed in saddle 34 in the position shown in FIG. 1, with the upper end in contiguous relation with grommet seal 42 and the bore thereof aligned with seal aperture 44.

When it is desired to fill the pipette to any desired extent, body member 16 is grasped in one hand in the manner illustrated in FIG. 1 so that the index finger and middle finger overlie actuating button 58 and 58 respectively. In order to draw the liquid into the pipette, button 58 is depressed to place the vacuum source 26 in direct communication with the upper end of pipette 22, resulting in a suction of the liquid into the pipette. The rate at which the liquid is drawn into the pipette is controlled by extent to which valve 54 is depressed. When the desired amount of liquid has been drawn into the pipette, button 58 is released by the finger, and the valve automatically returns to the inoperative position under urging of spring 60.

ln dispensing the liquid from the pipette, a similar procedure is followed except that actuating button 58 is depressed thereby placing air pressure source 22 in direct communication with the upper end of pipette 18 to expel fluid from the pipette in a well known manner.

With the apparatus of the present invention, liquids may be repeatedly drawn intoand expelled from a pipette, and the pipette is readily positioned in a very expeditious manner. Additionally, the structural arrangement of the present apparatus is comfortable to hold and the valves thereof are strategically positioned so that actuation thereof is readily accomplished by an easy and natural finger movement, so that no fatigue or other strain is experienced by the user even if used over a long period of time.

While there has been herein shown and described the presently preferred forms of this invention, it is to be understood that such has been done for purposes of illustration only, and that various changes may be made therein within the scope of the appended claims.

What is claimed is:

1. Apparatus for drawing liquids into, and expelling liquid from, a pipette or the like including:

a. a U-shaped body member,

b. the central portion of said U-shaped body member comprising a hand grip,

c. the leg portions of said U-shaped body member comprising spaced support means for the pipette,

d. means for holding the pipette in engagement with said leg portions,

e. a vacuum source,

f. a pressure source,

g. duct means extending through said body member connecting one end of the pipette with said vacuum source and pressure source, and

h. a pair of valve members carried by the hand grip in communication with said duct means,

i. one of said valve members being operative to place one end of the pipette in communication with said vacuum source,

j. the other of said valve members being operative to place one end of the pipette in communication with said pressure source.

2. The apparatus of claim 1, wherein:

a. each of said valve members includes a valve bore,

b. a plunger operable within said valve bore,

c. spring means for normally urging said plunger to the raised, inoperative position, and

d. a groove in the periphery of said plunger,

e. means for preventing communication between said groove and said duct means when said plunger is in the raised, inoperative position,

f. said groove establishing communication with said duct means when said plunger is depressed.

3. The apparatus 0 claim 2, wherein:

a. the plunger of each of said valve members extends from said hand grip in underlying relation with two fingers of the hand engaging said hand grip.

4. The apparatus of claim 3 with the addition of:

a. means for controlling the rate of flow through said duct means to the pipette when the plunger is depressed.

5. The apparatus of claim 4, wherein:

a. said means for controlling the rate of flow through said duct means includes a longitudinal groove in the peripheral wall of said plunger,

b. said groove extending longitudinally of said valve member,

c. the depth of said groove being reduced from top to bottom to permit a gradual increase in flow through said duct means as the plunger of said valve member is depressed.

6. Apparatus for drawing liquids into, and expelling liquids from, a pipette or the like including:

a. a body member of substantially U-shaped configuration,

b. the central prtion of said U-shaped body member comprising a hand grip,

c. the leg portion of said U-shaped body member comprising spaced support means for the pipette,

d. a vacuum source,

e. a pressure source,

f. duct means connecting one end of the pipette to said vacuum source and pressure source, and

. g. valve means carried by said hand grip portion and operatively engaged with said duct means for selectively placing one end of the pipette in communication with said vacuum source and pressure source.

7. The apparatus of claim 6, wherein:

a. the terminal of one of said leg portions is transversely arcuate to complement and receive a portion of the pipette periphery, and

b. means carried by said one of said leg portions engageable with the pipette for holding the latter in position.

8. Apparatus for drawing liquids into, and expelling liquids from, a pipette or the like including:

a. a body member,

b. said body member including a hand grip portion and a pipette supporting portion,

0. a vacuum source,

cl. a pressure source,

e. duct means connecting one end of the pipette to said vacuum source and pressure source,

f. valve means carried by said hand grip portion and operatively engaged with said duct means for selectively placing one end of the pipette in communication with said vacuum source and pressure source,

g. said valve means including a pair of valve members,

h'. each of said valve members comprising a valve bore and a plunger within the valve bore,

i. the valve bores of said pair of valve members being in communication with the pipette and said pressure source and vacuum source respectively.

j. means for normally urging each plunger to a raised inoperative position in the valve bore,

k. means in the valve bores of said valve members for preventing communication between the pipette and said pressure source and vacuum source respectively when said plunger is in the raised, inoperative position, and

1. means carried by each of said plungers for establishing communication between the pipette and said pressure source and vacuum source respectively when the plunger is depressed within the valve bore.

9. The apparatus of claim 8, wherein:

a. said means for normally urging each plunger to a raised inoperative position comprises a spring member.

10. The .apparatus of claim 9, wherein:

a. said means in the valve bore for preventing communication between the pipette and said pressure source and vacuum source respectively comprise sealing members interposed between said plunger and said body member.

11. The apparatus of claim 8, wherein:

a. said means carried by each of said plungers for establishing communication between the pipette and said pressure source and vacuum source respectively comprises a groove in the periphery of each of said plungers,

b. said groove establishing communication with said duct means when said plunger is depressed into the valve bore.

12. The apparatus of claim 11, with the addition of:

a. means for controlling the rate of flow through said duct means to the pipette when the plunger is depressed.

13. The apparatus of claim 12, wherein:

a. said means for controlling the rate of flow through said duct means includes a longitudinal groove in the periphery of each of said plungers,

b. the depth of said longitudinal groove being progressively more shallow from the top to the bottom thereof, whereby a gradual increase in flow through said duct means is effected as said plunger is depressed.

14. The apparatus of claim 13, wherein:

a. said plunger extends outwardly from said hand grip in underlying relation with two fingers of the hand engaging said hand grip. 

1. Apparatus for drawing liquids into, and expelling liquid from, a pipette or the like including: a. a U-shaped body member, b. the central portion of said U-shaped body member comprising a hand grip, c. the leg portions of said U-shaped body member comprising spaced support means for the pipette, d. means for holding the pipette in engagement with said leg portions, e. a vacuum source, f. a pressure source, g. duct means extending through said body member connecting one end of the pipette with said vacuum source and pressure source, and h. a pair of valve members carried by the hand grip in communication with said duct means, i. one of said valve members being operative to place one end of the pipette in communication with said vacuum source, j. the other of said valve members being operative to place one end of the pipette in communication with said pressure source.
 2. The apparatus of claim 1, wherein: a. each of said valve members includes a valve bore, b. a plunger operable within said valve bore, c. spring means for normally urging said plunger to the raised, inoperative position, and d. a groove in the periphery of said plunger, e. means for preventing communication between said groove and said duct means when said plunger is in the raised, inoperative position, f. said groove establishing communication with said duct means when said plunger is depressed.
 3. The apparatus o claim 2, wherein: a. the plunger of each of said valve members extends from said hand grip in underlying relation with two fingers of the hand engaging said hand grip.
 4. The apparatus of claim 3 with the addition of: a. means for controlling the rate of flow through said duct means to the pipette when the plunger is depressed.
 5. The apparatus of claim 4, wherein: a. said means for controlling the rate of flow through said duct means includes a longitudinal groove in the peripheral wall of said plunger, b. said groove extending longitudinally of said valve member, c. the depth of said groove being reduced from top to bottom to permit a gradual increase in flow through said duct means as the plunger of said valve member is depressed.
 6. Apparatus for drawing liquids into, and expelling liquids from, a pipette or the like including: a. a body member of substantially U-shaped configuration, b. the central prtion of said U-shaped body member comprising a hand grip, c. the leg portion of said U-shaped body member comprising spaced support means for the pipette, d. a vacuum source, e. a pressure source, f. duct means connecting one end of the pipette to said vacuum source and pressure source, and g. valve means carried by said hand grip portion and operatively engaged with said duct means for selectively placing one end of the pipette in communication with said vacuum source and pressure source.
 7. The apparatus of claim 6, wherein: a. the terminal of one of said leg portions is transversely arcuate to complement and receive a portion of the pipette periphery, and b. means carried by said one of said leg portions engageable with the pipette for holding the latter in position.
 8. Apparatus for drawing liquids into, and expelling liquids from, a pipette or the like including: a. a body member, b. said body member including a hand grip portion and a pipette supporting portion, c. a vacuum source, d. a pressure source, e. duct means connecting one end of the pipette to said vacuum source and pressure source, f. valve means carried by said hand grip portion and operatively engaged with said duct means for selectively placing one end of the pipette in communication with said vacuum source and presSure source, g. said valve means including a pair of valve members, h. each of said valve members comprising a valve bore and a plunger within the valve bore, i. the valve bores of said pair of valve members being in communication with the pipette and said pressure source and vacuum source respectively. j. means for normally urging each plunger to a raised inoperative position in the valve bore, k. means in the valve bores of said valve members for preventing communication between the pipette and said pressure source and vacuum source respectively when said plunger is in the raised, inoperative position, and l. means carried by each of said plungers for establishing communication between the pipette and said pressure source and vacuum source respectively when the plunger is depressed within the valve bore.
 9. The apparatus of claim 8, wherein: a. said means for normally urging each plunger to a raised inoperative position comprises a spring member.
 10. The apparatus of claim 9, wherein: a. said means in the valve bore for preventing communication between the pipette and said pressure source and vacuum source respectively comprise sealing members interposed between said plunger and said body member.
 11. The apparatus of claim 8, wherein: a. said means carried by each of said plungers for establishing communication between the pipette and said pressure source and vacuum source respectively comprises a groove in the periphery of each of said plungers, b. said groove establishing communication with said duct means when said plunger is depressed into the valve bore.
 12. The apparatus of claim 11, with the addition of: a. means for controlling the rate of flow through said duct means to the pipette when the plunger is depressed.
 13. The apparatus of claim 12, wherein: a. said means for controlling the rate of flow through said duct means includes a longitudinal groove in the periphery of each of said plungers, b. the depth of said longitudinal groove being progressively more shallow from the top to the bottom thereof, whereby a gradual increase in flow through said duct means is effected as said plunger is depressed.
 14. The apparatus of claim 13, wherein: a. said plunger extends outwardly from said hand grip in underlying relation with two fingers of the hand engaging said hand grip. 